add missing externs to repo

externs/webextension_polyfill/notifications/Static.hx

@@ -0,0 +1,35 @@
+package webextension_polyfill.notifications;
+
+typedef Static = {
+	/**
+		Creates and displays a notification.
+		
+		Creates and displays a notification.
+	**/
+	@:overload(function(options:CreateNotificationOptions):js.lib.Promise<String> { })
+	function create(notificationId:Null<String>, options:CreateNotificationOptions):js.lib.Promise<String>;
+	/**
+		Clears an existing notification.
+	**/
+	function clear(notificationId:String):js.lib.Promise<Bool>;
+	/**
+		Retrieves all the notifications.
+	**/
+	function getAll():js.lib.Promise<haxe.DynamicAccess<CreateNotificationOptions>>;
+	/**
+		Fired when the notification closed, either by the system or by user action.
+	**/
+	var onClosed : webextension_polyfill.events.Event<(notificationId:String, byUser:Bool) -> Void>;
+	/**
+		Fired when the user clicked in a non-button area of the notification.
+	**/
+	var onClicked : webextension_polyfill.events.Event<(notificationId:String) -> Void>;
+	/**
+		Fired when the  user pressed a button in the notification.
+	**/
+	var onButtonClicked : webextension_polyfill.events.Event<(notificationId:String, buttonIndex:Float) -> Void>;
+	/**
+		Fired when the notification is shown.
+	**/
+	var onShown : webextension_polyfill.events.Event<(notificationId:String) -> Void>;
+};